U3

Question 1

Driving force

Answer 1

force of gravity on slope

Question 2

Resisting force

Answer 2

force of friction on slope

Question 3

Cohesion

Answer 3

surface tension of water that holds soil grains together

Question 4

Porosity

Answer 4

the measure of pore space

Question 5

Pore space

Answer 5

the space existing between grains

Question 6

Lots of water in pore space

Answer 6

reduces cohesion

Question 7

Little water in pore space

Answer 7

increase cohesion

Question 8

Feldspar

Answer 8

abundant granitic mineral, weather to form clay minerals

Question 9

Kaolinite

Answer 9

layers held together by weak charges → soak up water, expand

Question 10

Smectite

Answer 10

open layers, swelling soil (weathered volcanic ash, extremely slippery)

Question 11

Quick clay

Answer 11

water-saturated muds prone to collapse and flow when disturbed, common on coasts

Question 12

How are quick clays disturbed?

Answer 12

liquefaction & water displacement (porosity)

Question 13

Daylighted beds

Answer 13

Exposed rock layers, often due to oversteeped roads that result in no resisting load, prone to slippage

Question 14

What force works on daylighted beds?

Answer 14

friction is the only force preventing sliding

Question 15

Rockfalls

Answer 15

vertical fractures, zones of weakness

Question 16

Rockslide

Answer 16

rock failure on a slope

Question 17

Debris flow

Answer 17

Water-laden soil and rock rush down slopes. 50-50 water & sediment

Question 18

Slump

Answer 18

drop-off, terracing effect

Question 19

Earthflow

Answer 19

Oversteepened land → patches of land slump on slope

Question 20

Creep

Answer 20

slow downslope movement, accelerated by freeze & thaw

Question 21

Karst topography

Answer 21

landscape characterized by many caves, sinkholes, and streams

Question 22

Groundwater

Answer 22

water in underground rock & soil pore space

Question 23

Carbonic acid

Answer 23

H20 (acidic rainwater) + CO2 (carbon dioxide) = carbonic acid (soluble in water, slowly dissolves limestone)

Question 24

Aquifer

Answer 24

porous rock layer that water soaks & travels through, typically used for groundwater mining

Question 25

Aquitard

Answer 25

a saturated but semi-permeable bed that prevents water from moving freely to a well/spring

Question 26

How does groundwater storage work?

Answer 26

Porous layer (aquifer) must be trapped by non-permeable layers (aquitard)

Question 27

Permafrost

Answer 27

arctic climates with in-ground temperatures below freezing year round (thawing = damage from ground settling)

Question 28

Discharge

Answer 28

the total volume of water flowing per unit of time

Question 29

Drainage area

Answer 29

streams collect water through groundwater seepage (water in porous soil) & watersheds (drainage basin, outlet)

Question 30

Gradient

Answer 30

the slope of a channel, it’s descent from highest to lowest elevation

Question 31

Sediment load

Answer 31

the amount of sediment in a stream, limited by stream velocity & volume

Question 32

Meandering stream

Answer 32

move from side to side, eroding & depositing at the same time

Question 33

Braided stream

Answer 33

broad network of river channels overloaded with sediment, locally clogs small streams

Question 34

Bedrock stream

Answer 34

high-energy stream in steep/mountainous areas, small sediment has all been carried out

Question 35

Levee

Answer 35

a ridge of sediment deposited naturally alongside a river by overflowing water & slowing velocity that drops suspended sediment load

Question 36

How does urbanization encourage flooding?

Answer 36

eliminating the area that water can soak up, causing rapid run-off

Question 37

Difference between flash & regional flood?

Answer 37

Flash floods are local, sudden, and dangerous; regional floods affect large geographic area that causes widespread damage, but is usually anticipated